There is an increasing demand for multiple-input multiple-output (MIMO) communication technology in wireless communication systems due to the need for higher channel capacity. In a MIMO system, low mutual coupling and high isolation between antennas are important for obtaining antenna diversity and high radiation efficiency. As such, achieving low mutual coupling and high isolation between neighboring antenna elements is a concern in MIMO antenna design, and many designs have been developed to improve isolation between neighboring antenna elements.
However, a competing concern in MIMO antenna design is the limited mobile device space, which requires a smaller antenna size. Reducing the size of MIMO antennas is often at odds with the goal of achieving low mutual coupling and high isolation between neighboring antenna elements. In view of the above, a need exists for an antenna design that successfully reduces the size of a MIMO antenna while retaining low mutual coupling and high isolation between neighboring antenna elements.